First, I don’t see why you called this church “hardcore Calvinistic”. I see nothing that indicates that in the least. “Protestant” perhaps, but not “hardcore Calvinistic”.
Second, it is not the ideas of the Reformation that directly leads to the downfall of these denominations. It is the abandoning of Biblical teachings to follow the traditions of men that leads to this outcome.
Well said! The "blame" lies not in the principles of the Reformation but in the loss of principles of those who lead.